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Positive-ion ESI mass spectrometry of regioisomeric nonreducing oligosaccharide fatty acid monoesters: In-source fragmentation of sodium adducts

✍ Scribed by Ignacio Pérez-Victoria; Alberto Zafra; Juan Carlos Morales


Book ID
102376148
Publisher
John Wiley and Sons
Year
2008
Tongue
English
Weight
182 KB
Volume
43
Category
Article
ISSN
1076-5174

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✦ Synopsis


Abstract

Structural characterization and differentiation of a novel group of regioisomeric monolaurate esters of the nonreducing trisaccharides raffinose and melezitose, and the nonreducing tetrasaccharide stachyose has been obtained using positive electrospray ionization (ESI) mass spectrometry with in‐source fragmentation. The surfactant nature and high polarity of these compounds make them appropriate analytes for being studied by conventional ESI‐MS. The position of the acyl chain in each particular regioisomer has been used as a reporter group that allows unambiguous rationalization of the fragmentation routes of the corresponding natriated molecular ions [M + Na]^+^. In all cases, the main fragment ions were produced through cleavage of the glycosidic bond involving two anomeric carbons, the C‐1′ and C‐2″ of the α‐D‐Glc__p__‐(1–2)‐β‐D‐Fru__f__ bond, and it was observed that sodium cation retention occurred on the heavier mass fragment of the two formed fragments, (e.g. di‐ or trisaccharide type vs monosaccharide type). Our results may help to better understand the fragmentation behavior of nonreducing oligosaccharides (as sodium adducts) in positive ESI mass spectrometry. Copyright © 2008 John Wiley & Sons, Ltd.